The goals of this study are: (1) To develop techniques for control of reproduction in laboratory-reared bullfrogs; (2) Control of disease in pre- and post-metamorphic stages; (3) To develop defined strains of the species suitable for biomedical research, research basic to medicine, and suitable for mass culture; (4) To define management techniques for both laboratory and commercial culture of this species. Significant results for 1978 include: (1) The Successful ovulation of wild-caught females from March through September and successful ovulation of lab-reared females using bullfrog pituitaries and progesterone; (2) ovulating preovulatory wild females held in the lab for two months; (3) establishment of twelve F1 lines selected for rapid growth and showing 2-3x growth rates over wild-type offspring; (4) controlled spermiation of laboratory males from 70 g and larger; (5) successful feeding of autoclaved larval feed; (6) demonstrated that the amino acid content of the larval feed alters the bacterial flora in the gut and may be useful in disease control, and (7) initiated immunization studies by use of osmotic force to transfer antigens into the larvae.